The operation of an internal combustion engine, for example a gasoline engine or a diesel engine, requires a controlling or regulating of the internal combustion engine, primarily in order to set the torque produced. For this purpose, in various subsystems of the controlling/regulating of the internal combustion engine, also called engine controlling, the quantities that influence the torque are controlled/regulated. The subsystems include what is known as a filling control, a mixture formation, and, in gasoline engines, an ignition. An important input quantity for the engine controlling is a current angular position of the internal combustion engine.
Additional important quantities include a current rotational speed, or a current angular speed.
In the mixture formation, the optimal time of injection is determined as a function of the current rotational speed and the current angular position of the internal combustion engine. In the ignition subsystem, the crankshaft angle is determined at which an ignition of the air-fuel mixture introduced during the mixture formation should take place. It is known to acquire the current angular position using a crankshaft sensor wheel fastened to a crankshaft, and a crankshaft sensor. In a four-stroke motor, one work cycle extends over 720° of crankshaft. Because here the crankshaft executes two complete rotations in one work cycle, the position within the work cycle that is determined using the crankshaft sensor is ambiguous. In order to resolve the ambiguity, use is made of what is known as a phase sensor and a camshaft sensor wheel connected to a camshaft in order to determine whether the current position is to be determined relative to the first rotation of the crankshaft (0 to 360°) or to the second rotation of the crankshaft (360-720°).
A failure of the component required for the determination of the current angular position can have the result that the current angular position can no longer be determined and the internal combustion engine can no longer be controlled. In order nonetheless to enable emergency operation of the internal combustion engine using an emergency driving function in case of disturbance of the crankshaft sensor, it is known to determine what is known as a substitute rotational speed using the phase sensor. The substitute rotational speed can then be used for a plausibility test relating to the rotational speed determined from the obtained crankshaft signals. In the case of a disturbance of the crankshaft sensor, an emergency driving function is thus capable of being realized. For this purpose, the camshaft sensor wheel must have a corresponding shape so that an engine position or rotational speed is able to be determined.
However, the angular position of the internal combustion engine (engine position) determined using the camshaft sensor, and the rotational speed determined therewith, is often very imprecise, so that the emergency driving function enables only an unsatisfactory operation of the internal combustion engine. However, in the case of a disturbance of the crankshaft sensor, disturbance of the phase sensor or of the camshaft sensor wheel regularly has the result that the internal combustion engine can no longer be operated. Moreover, in known systems it can occur that it cannot be determined whether disturbance of the crankshaft sensor or of the phase sensor is present. In this case, an emergency driving function usually also cannot be realized.
In addition, the phase sensor, the camshaft sensor wheel, the cabling, and the fastening of these components is cost-intensive, so that it would be desirable to be able to do without these components, in particular given production with high piece counts.